International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 07 Issue: 03 | Mar 2020
p-ISSN: 2395-0072
www.irjet.net
DESIGN AND FABRICATION OF PICK AND PLACE MICRO-GRIPPERS L .V. V. NAGA PRASAD1, M. GOPI KRISHNA2, SK. GHOUSE MOINUDDIN3, V. NAGA SAI KUMAR4, P.RAJESH5, V. VARA PRASAD6 M.Tech 1,2,3,4,5,6Department
of Mechanical Engineering, DMSSVH College of Engineering, Machilipatnam, Krishna district, Andhra Pradesh, India. ----------------------------------------------------------------------***--------------------------------------------------------------------ABSTRACT: This paper presents design and a simple fabrication process that allows isolated metal tracks to be easily defined on the surface of 3D printed micro-gripper components. The process makes use of a standard low cost fused deposition modelling system to quick deposit of thin film ‘PLA’ layers on to the surface of 3D printed polymer micro parts. As the end-effectors of micromanipulation systems, micro-grippers are crucial point of such systems for efficiency and reliability. This paper deals with design and fabrication of recently used micro-grippers. They are designed by uni-graphics software (NX 11.0) and fabricated by 3D printing. The designed and fabricated micro-grippers are offering stroke extending from 50 µm to 2mm(approximately) andwith maximum applied forces varying from 0.1mN to 600mN.These grippers are used to pick, hold and place macro/micro-components, which are widely used in the field of assembly. Keywords: micro-gripper; microcomponents; micromanipulation; FDM printing; Additive Manufacturing; PLA Material; 1. INTRODUCTION: The field of mechanical micro-machining deals with the production of miniature 3D components such as micro-shafts, micro-nuts, micro-spiral inductors, micro-motors etc; using a variety of engineering materials in the sub-millimetre (1-999 µm) range and bridges the gap between nano-scale and ‘macro scale’ manufacturing [1]. To handle these components, micro-grippers are required. The general requirement of a micro-gripper is that it should hold with sufficient force without breaking the component and release the components at a specified position. The positional uncertainty during assembly should be well defined and components should not get damaged. Microgrippers are used in the assembly of ‘micro components’ in various fields such as electronics, information technology, optics, medicine, biology areas like diagnostics, biological cells, biopsy tissue sampling, tissue engineering and minimally invasive surgery [2]. Grippers are classified based on the principles used such as mechanical, piezoelectric, thermal, electromagnetic, vacuum, etc; [2-5]. Different kinds of micro-grippers have been designed and fabricated since 1990. Among these mechanical microgrippers have high mechanical stability and can be used where electrical and thermal environments cannot be tolerated. The actuation is obtained by applying mechanical forces on a segment of micro-gripper. These forces are given by piezoelectric motor [6], micro drive control knob with tether cable drive [7], piezoelectric bar assembly [8] and micrometre turning with push and pull displacement causing tensile stress [9]. Hydraulic and pneumatic grippers are also used [10]. Michel Goldfarb and Nikola Celanovic developed a flexure based gripper [11]. Mechanically actuated silicon micro-gripper for handling micro and nano particles ranging from a few micrometres down to hundred nano metres. This gripper was designed to manipulate microstructures in the range of 5 µm to 50 µm. The design is based on push and pull displacement. It was actuated both mechanically and by using a piezoelectric stack. It was fabricated using traditional MEMS techniques and was able to open upto 130 µm. This is mainly due to the manufacturing process used by them cannot fabricate complicated three dimensional structures. The additive manufacturing techniques have been used in this work. Additive manufacturing is the process of fabricating objects from 3D model data by building materials layer by layer. This process allows highly complex geometries to be created directly from 3D CAD data without any tooling. In this paper, polymer based mechanical microgrippers that can hold micro components are designed using uni-graphics software (NX 11.0). The fabrication is carried out using FDM printing process which is an additive manufacturing process. The designed and fabricated micro-grippers are offering stroke extending from 50 µm to approximately 2mm and with maximum applied forces varying from 0.1mN to 600mN. 2. DESIGN : Micro grippers are designed using UNI-GRAPHICS (NX11.0) software. The grippers are made using PLA (Poly Lactic Acid) material. The PLA material microgrippers are used in electrical power shocks to be observed in the pick and place microchips, pick the wirings etc. There are number of models to be designed
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for number of applications such as automobiles industries, medical fields, and electrical fields etc. In micro biology to understand the behaviour and interactions between cells as well as to ensure about the heterogeneity of the cell population, it is necessary that
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